1. Field of the Invention
The present invention relates to cardiopulmonary apparatus and methods for preserving the life of a patient by providing extracorporeal blood oxygenation and circulation in which a patient's blood is introduced via a venous connection into the extracorporeal blood circuit and is pumped by a blood pump via different blood-conducting components to an arterial connection from where the blood is again pumped into the patient's blood circulation. The apparatus and methods are useful in a variety of settings including hospitals, remote areas, accident sites, and during transport, for example in an ambulance, boat, or helicopter. The apparatus, methods, and systems are necessary for sustaining the life of a patient while the heart is stopped during transvascular heart valve repair or replacement surgery and/or during periods of pulmonary failure such as sudden acute respiratory distress syndrome.
2. Description of Related Art
Time is critical in initiating treatment of severe acute trauma, particularly when cardiac function, pulmonary function, or both is impaired. Often, a heart-lung machine can be necessary or critical in the field or during patient transport to a hospital. Heart-lung and cardiopulmonary assist machines are known but their use in emergency, transport, and field situations is hindered, in part, by the relatively long period of time and the requirement for well trained specialists for priming the machines and safely bringing them into operation.
Additionally, during machine priming, a liquid is used to fill the blood-conducting components of the heart-lung machine. The priming liquid must be vented or deaerated prior to connection with the patient's vascular system and initiating heart-lung machine operation in order to eliminate air bubbles, which can cause thrombosis. When such an extracorporeal blood circuit is used, air bubbles may form inside the blood circuit and air present in the blood circuit while putting the extracorporeal blood circuit into operation can enter into the blood. An air bubble entering into the patient's blood circulation can cause a fatal air embolism in the worst case. Air bubble detectors can detect air bubbles in the extracorporeal blood circuit to trigger a visual or acoustic alarm signal so that the blood supply to the patient can be stopped. Subsequently, medical personnel on hand must act as fast as possible to eliminate the problem.
The apparatus and methods of the present invention overcome the aforementioned limitations of prior art heart-lung machines by providing for a compact and portable heart-lung machine that can be primed and ready for operation in less than 10 minutes with little or no human intervention. The present heart-lung machine may be self-contained and include an internal power supply, and/or may be connected to an external power supply such as an on-board power supply of an emergency land, air, or sea transport vehicle. Furthermore, no perfusion specialist is required for set up or operation and, in some embodiments, the machine may be constructed to meet requirements for regulatory approval for transport use. The machine may for instance in particular meet requirements of the EN 1789 standard for use in humid environments, water subjection, and pass shake and crash tests involving up to 9-10 g forces.
The present invention is made possible, in part, by a number of advancements in heart-lung machine technology including a fast-closing clamp, a fast-priming extracorporeal blood oxygenation, deaeration and circulation system, and an air bubble detection system, which are described in co-assigned U.S. application Ser. No. 11/284,515 filed Nov. 22, 2005; Ser. No. 11/366,342, now U.S. Pat. No. 7,597,546 filed Mar. 2, 2006; Ser. No. 11/366,914, now U.S. Pat. No. 7,367,540 filed Mar. 2, 2006; and Ser. No. 11/544,524 filed Oct. 30, 2006, which are incorporated by reference herein in their entirety. The apparatus and methods of the invention are also made possible, in part, by a multistage air removal system and various other components and procedures described herein.